The invention relates to writing implements in general, and more particularly to improvements in ball point pens. Still more particularly, the invention relates to improvements in means for holding the ball and in means for supplying ink to the ball in a ball point pen.
German Pat. No. 27 12 058 to Nakagawa et al. discloses a ball point pen wherein the ball is mounted in the front end of a tubular metallic holder and abuts a plastic seat. An advantage of such pen is that the holder is made of wear-resistant metallic material but the ball can roll along a plastic seat and encounters much less resistance than if the seat were made of a metallic material. A drawback of the patented pen is that the cost of making and installing a plastic seat in a tubular metallic holder is relatively high. The seat is produced in a separate step and is thereupon inserted into the holder. This necessitates highly accurate machining of the internal surface of the holder, the making of the seat with a very high degree of precision, and accurate insertion of the seat into the holder. Moreover, care must be exercised to ensure that the prefabricated seat in the prefabricated tubular holder will not interfere with proper flow of ink to the ball. To this end, the properly inserted seat is formed with a centrally located ink supplying passage which terminates at the exterior of the ball in the front end of the holder. When the pen is in use, the front end of the channel is sealed by the ball. It has been found that the making of a channel in the inserted seat contributes significantly to the cost of the writing implement and that such centrally located channel does not always suffice to ensure the delivery of requisite quantities of ink to the working end of the pen. As a rule, the delivery of ink is interrupted when the user is in the process of making long lines on and/or of rapidly moving the ball along a piece of paper or the like.
A similar ball point pen is disclosed in German Pat. No. 887 924 to Schmidt. The patented pen has a metallic tube which carries the ball and is inserted into a plastic support which delivers ink to the interior of the tube behind the ball.
German Utility Model No. 16 87 504 of Petersson discloses a ball point pen wherein a plastic tube is inserted into the metallic ball holder and serves as a seat for the ball as well as to deliver ink to the periphery of the ball.